Systems and methods for recycling plastic

ABSTRACT

Systems and methods for recycling waste plastic can convert the waste plastic into a form of purified crude oil that includes one or more organic molecular species and that is free, or substantially free, of impurities such as acids and metals. In some systems and methods, the plastic is heated under vacuum conditions to effect depolymerization of the plastic, which yields a vapor, and the vapor is then directly contacted with a pH adjusted solution in a vapor treatment system. In some systems and methods, a continuous batch process is employed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of prior U.S. patentapplication Ser. No. 11/510,489, filed Aug. 24, 2006, titled SYSTEM ANDMETHOD OF RECYCLING PLASTICS now U.S. Pat. No. 7,758,729; thisapplication is a continuation-in-part of prior U.S. patent applicationSer. No. 12/751,911, filed Mar. 31, 2010, titled DEVICES, SYSTEMS, ANDMETHODS FOR RECYCLING PLASTIC now allowed; and this application claimsthe benefit of U.S. Provisional Application No. 61/352,793, filed Jun.8, 2010, titled SYSTEMS AND METHODS FOR RECYCLING PLASTIC. The entirecontents of each of the foregoing applications are hereby incorporatedby reference herein.

TECHNICAL FIELD

The present disclosure relates generally to the recycling of plastic.Certain embodiments relate more specifically to systems and methods forvaporizing plastic and recovering organic molecules from the resultantvapor.

BRIEF DESCRIPTION OF THE DRAWINGS

The written disclosure herein describes illustrative embodiments thatare non-limiting and non-exhaustive. Reference is made to certain ofsuch illustrative embodiments that are depicted in the figures, inwhich:

FIG. 1 is a schematic flow diagram of an embodiment of a plasticrecycling system;

FIG. 2 is a schematic flow diagram of another embodiment of a plasticrecycling system;

FIG. 3 is a schematic flow diagram of another embodiment of a plasticrecycling system;

FIG. 4 is a cross-sectional view of an embodiment of a baffle that iscompatible with an embodiment of a condenser that may be used in thesystem of FIG. 3;

FIG. 5 is a schematic flow diagram of an embodiment of a vacuum systemthat is compatible with the plastic recycling system of FIG. 3;

FIG. 6 is a schematic flow diagram of an embodiment of a series ofheating systems and containers in which the containers are commonlyjoined to a gas transfer line, wherein plastic feedstock within thecontainers is being vaporized and removed from the containers in acontinuous batch process;

FIG. 7 is a schematic flow diagram of another embodiment of a plasticrecycling system;

FIG. 8 is a schematic flow diagram of another embodiment of a plasticrecycling system; and

FIG. 9 is a schematic flow diagram of a cleaning system and a reservoirthat can be used in another embodiment of a plastic recycling systemsuch as the recycling system of FIG. 3.

DETAILED DESCRIPTION

Certain embodiments of systems and methods described herein areconfigured for efficient recycling of plastic. Some systems and methodscan quickly and simply convert waste plastics into one or more purifiedorganic molecular species, which can be considered as a crudehydrocarbon material or crude oil. The crude oil may be readily stored,transported, and/or refined into fuel or other commercially relevantmaterials.

In some embodiments, a quantity of waste plastic feedstock can beintroduced into a sealable cartridge or container. The container can beheated under vacuum conditions such that the plastic feedstocktransitions into a vapor (e.g., one or more gases), which can be removedfrom the cartridge for further processing. For example, the vapor can beintroduced into a condenser and directly contacted with a pH adjustedsolution, which can, in some instances, absorb a portion of the vaporand condense another portion thereof. The condensed material cancomprise one or more organic molecular species that can be termed hereinas a crude oil. The crude oil can be separated from the other portionsof the vapor that are absorbed into the pH adjusted solution, and thusthe crude oil can be of a clean or purified quality such that it may bereadily refined from its crude state.

Various illustrative embodiments of inventive systems and methods willnow be described. Advantages of the systems and methods, as well asfeatures and steps thereof, respectively, will be apparent from thedisclosure that follows.

FIG. 1 depicts a process flow diagram of an embodiment of a plasticrecycling system 100. The plastic recycling system 100 includes aheating system 102 that is configured to deliver heat 104 to a plasticfeedstock 106. The heating system 102 can comprise any suitable heatingmechanism, such as, for example, a combustion burner, a fluidized bedburner, a retort, or any other such heating system. In someapplications, the heating system 102 operates at a high and steadytemperature.

The plastic feedstock 106 can comprise waste plastics of one or morevarieties (e.g., mixed plastics), and may include trace amounts ofnon-plastic contamination or impurities. For example, the impurities maybe of an external nature (e.g., water, foodstuffs, labeling, soil,paper, or cellulose waste) or may result from internal amendments (e.g.,glass, metal, iron, bromine, and/or chlorine). The plastic feedstock 106may be provided in a ground, chipped, or other form that can promote thetransfer of heat thereto.

The heat 104 provided by the heating system 102 can be sufficient tocrack or depolymerize the plastic feedstock 106 and convert at least aportion thereof into a vapor 108. The vapor 108 can include one or moregaseous organic species, one or more gaseous inorganic species, and/orone or more varieties of entrained particles. In particular, the vapor108 can include depolymerized non-polar organic gases, which may bedesirable for collection and refinement, and which can be mixed withimpurities. The organic gases can include, for example, one or moreparaffins, olefins, naphthenes, aromatics, and/or other classes ofhydrocarbon materials. The mixed-in impurities can include, for example,inorganic acids (e.g., hydrochloric acid, hydrobromic acid), entrainedmetals or metalloids (e.g., cadmium, iron, antimony); and/or organicacids (e.g., terephthalic acid). In some embodiments, the vapor 108 mayinclude additional molecular species, such as polar organic molecules,which may or may not be collected with the non-polar organic molecules.For example, the vapor 108 can include one or more alcohols, ketones,ethers, phenols, carboxylic acids, or other polar organic molecules.

In some embodiments, the plastic feedstock 106 may be heated undervacuum conditions, or under negative pressure. In other embodiments, theplastic feedstock 106 may be heated under positive pressure. In stillother or further embodiments, the plastic feedstock 106 may be heatedunder atmospheric pressure conditions, or under any suitable combinationof the foregoing (e.g., the pressure may be varied during a heatingevent).

The vapor 108 can be delivered to a vapor treatment system 110 thateffects a phase change of at least a portion of the vapor 108 such thatcertain molecules transition from a gaseous state to a liquid state. Thevapor treatment system 110 may also be referred to as a vapor treatmentunit or a vapor treatment vessel. The illustrated vapor treatment system110 includes a pH adjusted solution 112 that is used to effect thecondensation. Moreover, the pH adjusted solution 112 can be configuredto absorb at least a portion of the impurities from the vapor 108.Embodiments of the solution 112 can readily absorb organic acids,inorganic acids, metals, metalloids, and/or certain polar organicmolecules. The term “pH adjusted solution” is used in a broad sense andincludes solutions that are not pH neutral and that exhibit any or allof the various properties described herein. For example, a pH adjustedsolution can be formulated to remove impurities from the vapor 108, andin further embodiments, can be immiscible with condensed oils so as tobe readily separated therefrom. For example, in some embodiments, the pHadjusted solution 112 can comprise an acidic solution, which may, insome cases, be strongly acidic. In further embodiments, the pH adjustedsolution 112 can comprise a buffered aqueous solution adjusted to adesired pH value. In various embodiment, the pH adjusted solution 112can have a pH value that is less than 7, less than about 6.5, less thanabout 6, less than about 5.5, less than about 5, less than about 4, orless than about 3.

The pH adjusted solution 112 can include one or more chemical amendmentsof any suitable variety to achieve the desired properties of thesolution. Such properties can include, for example, the ability toremove one or more impurities from the vapor 108 and/or a highimmiscibility with oil. Adjustment or optimization of one or more offoregoing properties may be achieved by altering the concentration ofthe one or more chemical amendments within the pH adjusted solution 112.For example, the presence, combination, and/or concentration of one ormore materials within the pH adjusted solution 112 can optimize removalof contaminants from the vapor 108 as it interacts with the pH adjustedsolution 112. In various embodiments, the pH adjusted solution caninclude strong and/or weak inorganic acids (e.g. hydrochloric acid,acetic acid), one or more pH buffer solutions (e.g., acetic acid+sodiumacetate), one or more chelating agents (e.g., ethylenediaminetetraaceticacid (EDTA)), and/or one or more coagulants and/or flocculants (e.g.calcium hydroxide, polyacrylamide).

The vapor treatment system 110 can be configured to effect directcontact between the vapor 108 received therein and the pH adjustedsolution 112, as depicted at the broken arrow 114. For example, asfurther discussed below, in some embodiments, the pH adjusted solution112 may be sprayed into contact with the vapor 108, whereas in otherembodiments, the vapor 108 may be bubbled through the solution 112. ThepH adjusted solution 112 can absorb or dissolve portions of the vapor112 (e.g., organic acids, inorganic acids, metals, metalloids, and/orcertain polar organic molecules). The pH adjusted solution 112 also canbe provided at a lower temperature than that of the vapor 108 such thatthe solution 112 condenses at least those portions of the vapor 112 thatare immiscible therein (e.g., non-polar organic molecules).

Those portions of the condensed vapor 108 that are immiscible in the pHadjusted solution 112 (i.e., the hydrophobic portions) can be readilyseparated from the solution 112, as indicated at the broken arrows 116.In some embodiments, the separation (or at least one or more stagesthereof) takes place within the vapor treatment system 110, whereas inother embodiments, the separation (or at least one or more stagesthereof) takes place within a separator that is independent of the vaportreatment system 110 (see, e.g., FIG. 2).

In some embodiments, the immiscible portions are removed from the vaportreatment system 110 as a form of crude oil 118. The crude oil 118 thuscan have few or no impurities, as the impurities that were present inthe plastic feedstock 106 are dissolved or absorbed into the pH adjustedsolution 112. In some embodiments, at least some of the dissolved orabsorbed impurities can remain within the pH adjusted solution 112within the vapor treatment system 110. For example, in some instances,after the pH adjusted solution 112 has amassed the impurities, it maycontinue to be used within the vapor treatment system 110, such that theimpurities are not removed (at least not immediately) from the vaportreatment system 110. In other or further embodiments, dissolved orabsorbed impurities are removed from the vapor treatment system 110separately from the oil 118, as shown at the arrow 120.

Certain classes of polar organic molecules may only partially (or atleast partially) partition into the pH adjusted solution 112. Forexample, a portion of certain alcohols, ketones, ethers, phenols,carboxylic acids, and/or other polar organic molecules may partitioninto the pH adjusted solution 112 and another portion thereof maypartition into the crude oil 118. Accordingly, in some embodiments,crude oil 118 that includes a portion of a species of polar organicmolecules may be separated from a pH adjusted solution 112 that containsanother portion of the species of polar organic molecules.

The vapor 108 may include portions that do not condense within the vaportreatment system 110 and are not absorbed by the pH adjusted solution112. Such non-condensable gases 121 can be removed separately from thevapor treatment system 110, and may be combusted or disposed of in anyother suitable manner.

In various embodiments, the vapor treatment system 110 may operate undervacuum conditions, or under negative pressure. In other embodiments, thevapor treatment system 110 may operate under positive pressure. In stillother or further embodiments, the vapor treatment system 110 may operateunder atmospheric pressure conditions, or under any suitable combinationof the foregoing (e.g., the pressure may be varied during a condensingevent).

The system 100 can be well suited for quickly cracking or depolymerizingthe plastic feedstock 106. For example, in some embodiments, heating ofthe plastic feedstock 106 and conversion thereof into the vapor 108 canbe performed at high temperatures at which a variety of differentmolecular species may be gasified simultaneously. Such differentmolecular species might have different vaporization temperatures at agiven pressure, and a temperature at which the plastic feedstock 106 isheated can exceed this temperature for some or all of the molecularspecies. The molecular species can then be separated from each otherwhen the vapor 108 is delivered to the vapor treatment system 110, aspreviously described. Accordingly, the system 100 can operate withoutthe heating system 102 slowly heating up and occasionally holding steadyat various discreet temperature levels along the way so as to allow forindividual molecular species to be gasified sequentially. It is to beappreciated, however, the system 100 may also be used in an operationalmode in which the heating system 102 and the plastic feedstock 106progress through a series of sequential heating steps or levels, as justdescribed.

FIG. 2 depicts a process flow diagram of another embodiment of a plasticrecycling system 100, which resembles the system 100. The system 100includes a heating system 102 that provides heat 104 to a plasticfeedstock 106. The plastic recycling system 100 further comprises asealable container 122 that retains the plastic feedstock 106 during theheating. The container 122 can be configured to hold a negative pressuretherein.

The system 100 can include a vacuum system 124 that is configured tomaintain a negative pressure within the container 122 and within a vaportreatment system 110. The vacuum system 124 can continuously evacuategases from the container 122 such that depolymerization of the plasticfeedstock 106 occurs in an oxygen-deprived or oxygen-free environment.The vacuum system 124 draws the vapor 108 into the vapor treatmentsystem 110, where it is contacted by the pH adjusted solution 112. Thevacuum system 124 draws the non-condensable gases 121 from the vaportreatment system 110, and may distribute them to a combustion unit orother suitable disposal device.

The system 100 includes a separator 128 that receives an emulsion 126 ofcondensed material from the vapor treatment system 110. The emulsion 126can comprise crude oil 118 that includes a small amount of the pHadjusted solution 112 entrained therein. The separator 128 can beconfigured to separate the crude oil 118 from the pH adjusted solution112 based on the difference in relative density between these materials.For example, the separator 128 can comprise a settling tank that allowsgravitational separation of the solution 112 from the crude oil 112. Inother embodiments, the separator 128 may comprise a centrifuge.

FIG. 3 illustrates another embodiment of a plastic recycling system 200,which can resemble the plastic recycling systems 100, 100 describedabove in certain respects. Accordingly, like features are designatedwith like reference numerals, with the leading digits incremented to“2.” For example, the plastic recycling system 200 includes a heatingsystem 202, a sealable container 222, a vapor treatment system 210, avacuum system 224, and a separator 228. Likewise, the vapor treatmentsystem 210 includes a pH adjusted solution 212 such as the pH adjustedsolution 112 described above. Relevant disclosure set forth aboveregarding similarly identified features thus may not be repeatedhereafter.

The illustrated heating system 202 includes a burner 230 and a heatingplenum 232. The burner 230 can comprise any suitable combustion burner,which may be configured to run on any suitable fuel. The fuel may besupplied by a fuel train 234, such as natural gas or propane piping. Thefuel train 234 can include any suitable combination of flow switches andvalves (not shown) to allow for the desired amount of fuel to bedelivered to the burner 230. Fuel from the fuel train 234 can bedelivered via any suitable fuel delivery line 235, such as conduit orpiping.

The burner 230 can be in fluid communication with a combustion blower236 and a circulation fan 237, each of which may have variable speedcapabilities. The combustion blower 236 supplies fresh air to the burner230, whereas the circulation fan 237 circulates heated exhaust from theheating plenum 232 back to the burner 230. The circulation fan 237 alsocan selectively draw in fresh air to provide a desired exhaust/airmixture to the burner 230. The heating system 202 can comprise anysuitable arrangement of ducts 238 for transporting air from one portionof the heating system 202 to another.

The heating plenum 232 is configured to selectively receive therein thesealable container 222, which may also be referred to as a cartridge.When situated within the heating plenum 232, the container 222 can seal,or substantially seal, the plenum such that heated air may circulatewithin the heated plenum but not escape into the surrounding atmosphere.Illustrative examples of heating plenums 232 and containers 222 that maybe used with the plastic recycling system 200 are disclosed in U.S.patent application Ser. No. 12/791,911, filed Mar. 31, 2010, titledDEVICES, SYSTEMS, AND METHODS FOR RECYCLING PLASTIC.

The container 222 can retain a quantity of plastic feedstock 206therein, which can be melted and vaporized as a result heat deliveredthereto by the heating plenum 232, as further discussed hereafter. Inthe illustrated embodiment, the heating plenum 232 includes a sidewall240 and an inner conduit 242, which rises upwardly at an interior of thesidewall 240. The sidewall 240 can include a series of ports (not shown)through which heated air can be delivered inwardly (e.g., toward theinner conduit 242), and the inner conduit 242 can include a series ofports 243 through which heated air can be delivered outwardly (e.g.,toward the sidewall 240).

The sidewall 240 can be in fluid communication with a first duct line238 from the burner 230, and the inner conduit 242 can be in fluidcommunication with a second duct line 238 from the burner 230. A damper244 can be situated relative to the first and second duct lines 238 soas to control the relative amount of heated air that is delivered to thesidewall 240 and to the inner conduit 242.

Heated exhaust that has been used to heat the container 222 can beremoved from the heating plenum 232 via a separate duct line 238 andcirculated to the burner 230 by the fan 237. At least a portion of theheated exhaust may be diverted and delivered to a heat exchanger 246 byopening a valve 248 and activating a venting fan 249. The heat exchanger248 is described further below.

Although the illustrated embodiment of the heating system 202 usesheated air to heat the container 222 and its contents, it is to beappreciated that any other or further suitable mechanisms for heatingthe container 222 and its contents are also possible. For example, aheated fluid other than air (e.g., a heated liquid) may be circulatedthrough the heating plenum 232. In other or further embodiments, heatingmechanisms may include electrical direct contact heating, inductionheating, or radiant heating.

The heating system 202 can further include a variety of sensor andcontrol components. For example, the heating system 202 can include oneor more pressure sensors 250 and/or temperature sensors 252, which canprovide to a subsystem controller 254 various data regarding theoperation of the burner 230 and the amount of heat being delivered tothe container 222. The sensors 250, 252 can communicate with thesubsystem controller 254 in any suitable manner, such as by wired orwireless connection. In the illustrated embodiment, communication lines(e.g., electrical wires) connect the sensors 250, 252 to the subsystemcontroller 254. Likewise, communication lines can connect othercomponents of the heating system 202 (e.g., the blower 236 and the fan237) to the subsystem controller 254. The communication lines are notshown in FIG. 3 so as not to obscure the drawing.

The subsystem controller 254 can alter operational parameters of theheating system 202 in response to data received from the sensors 250,252, and/or as a result of other programming. For example, if it isdetermined from temperature sensors 252 that are associated with theinner conduit 242 and the sidewall 240 that the temperature of heatedair being delivered to an inner portion of the container 222 isdeficient, the control system 254 can compensate by changing a settingof the damper 244 so that more heat is delivered to the inner conduit242 and less is delivered to the sidewall 240. In some applications, itmay be desirable to selectively alter the relative amounts of heatdelivered to a peripheral region and a central region of the container222 over the course of a heating cycle. In some instances, if it isdetermined that all temperatures throughout the heating plenum 232 aretoo low, the control system 254 may increase a speed of the blower 236and/or the fan 237. In other or further embodiments, any desiredalteration to the operational parameters of the heating system 202 maybe effected manually.

A master control system 255 may be configured to communicate with thesubsystem controller 254 (e.g., via an Ethernet cable or other suitablecommunication device, whether wired or wireless), and may also beconfigured to communicate with additional subsystem controllers 256,258, etc. that are each dedicated to other subsystems of the plasticrecycling system 200. For example, separate subsystem controllers 256,258 may be dedicated to the vapor treatment system 210 and the vacuumsystem 224, respectively. In some embodiments, the subsystem controllers254, 256, 258 are situated locally (e.g., near the various subsystemswith which they are associated), whereas the master control system 255may be situated in a supervisory station in which an operator canmonitor the instantaneous status of the multiple subsystems of thesystem 200 and can make changes thereto as desired, whether onsite oroffsite.

For the sake of convenience, the subsystem controller 254, 256, 258associated with a particular component may not be identified hereafter,nor will it be explicitly stated that a particular subsystem controller254, 256, 258 and/or the master control system 255 is able to monitorand/or control the operation of a particular component of the plasticrecycling system 200, although such is understood. It is also noted thatsteps or control events discussed herein which can be effected thecontrollers 254, 256, 258 and/or the master control system 255 may beembodied in machine-executable instructions that are to be executed by ageneral-purpose or special-purpose computer (or other electronicdevice). Alternatively, the steps or control events may be performed orinstigated by hardware components that include specific logic forperforming the steps or control events, or by a combination of hardware,software, and/or firmware. Some or all of the steps may be performedlocally (e.g., via a subsystem controller) or remotely (e.g., via themaster control system 255).

As previously discussed, the sealable container 222 may be selectivelycoupled with the heating plenum 232 or removed therefrom. In someembodiments, the container 222 is positioned externally to the heatingplenum 232 for filling. A lid 260 is removed or otherwise opened topermit entry of the plastic feedstock 206. Once the container 222 hasbeen filled, the lid 260 can then be closed and the container 222 can behoisted (e.g., via a crane) into the heating plenum 232. The container222 can cooperate with the heating plenum 232 to prevent heated exhaustgases from exiting from the heating plenum 232 at a connection interfacebetween the container 222 and the heating plenum 232.

An evacuation port 261 of the container 222 can be connected to a gastransfer line 262. The gas transfer line 262 can be in fluidcommunication with the vapor treatment system 210 which, in turn, can bein fluid communication with the vacuum system 224. Accordingly,connection of the gas transfer line 262 to the evacuation port 261 canplace the contents of the container 222 under vacuum, and the heating ofthe contents thus may take place in an oxygen-deprived or oxygen-freeenvironment.

As the container 222 is heated, the plastic feedstock 206 can melt andeventually gasify or vaporize. The resultant vapor 208 is drawn from thecontainer 222 through the evacuation port 261, through the gas transferline 262, and then into the vapor treatment system 210. In certainembodiments, the gas transfer line 262 includes a knock out tank 264,which can have a volume greater than that schematically depicted in FIG.3. The knock out tank 264 can comprise a container that acts as afailsafe in the event that the contents of the container 222 are rapidlyforced through the evacuation port 261, which could result from a largepressure fluctuation within the container 222 (e.g., due to an undesiredignition of gases). Such expelled contents can be collected in the knockout tank 264 and prevented from entering the vapor treatment system 210.In other embodiments, the knock out tank 264 is omitted (see FIG. 7).

A pressure sensor 266 and a temperature sensor 268 can be positioned inthe gas transfer line 262 to monitor the pressure and temperature of thevapor 208 as it exits the container 222. In some embodiments, one ormore of the temperature and pressure readings can be used to determinewhen vaporization of the plastic feedstock 206 is at or near completionsuch that the container 222 is ready to be removed from the heatingplenum 232 and replaced with a filled container 222. For example, insome embodiments, a heating temperature within the heating plenum 232can be maintained at a substantially constant level or set point value(e.g., at about 1100 degrees Fahrenheit, in some embodiments). Atemperature of the vapor 208 can rise to a maximum level (e.g., atime-averaged maximum level) during the heating, and can steadily remainnear the maximum level (e.g., can sustain only minor fluctuations) asthe vaporization continues. As the process nears completion and fewergases are created, the temperature of the vapor 208 exiting thecontainer 222 can drop. A size of this drop can signal that thecontainer 222 should be replaced. In various embodiments, a replacementevent may be signaled when the temperature of vapor 208 drops within arange of from about 10 to about 30 percent of the maximum level, ordrops within a range of from about 15 to about 25 percent of the maximumlevel. In some embodiments, a replacement event may be signaled with thetemperature drops by an amount equal to or greater than about 15, 20,25, or 30 percent. In other or further embodiments, a replacement eventmay be signaled when the temperature drops from the maximum level by noless than about 80, 90, or 100 degrees Fahrenheit. In still other orfurther embodiments, a replacement event may be signaled by the passageof no less than about ½, ¾, or 1 hour after the maximum level isreached.

With reference to FIGS. 3 and 4, the vapor 208 can be introduced intothe vapor treatment system 210 in any suitable manner. In theillustrated embodiment, the vapor treatment system 210 includes acondenser 270 and a reservoir 286. As shown in FIG. 3, in someembodiments, the vapor 208 is introduced into a condensing tower 271 ofthe condenser 270 substantially without altering a trajectory of thevapor 208. As shown in FIG. 4, in other embodiments, the vapor 208encounters a baffle 272 upon entering the condensing tower 271. Thevapor 208 can initially hit a guard plate 274, and can then be routeddownward and outwardly about a bottom edge 276 of the baffle 272. Thebaffle 272 can be configured to provide the vapor 208 with an even flowpattern. In particular, the baffle 272 can cause the vapor 208 to risein a uniform distribution about a periphery of the bottom edge 276.

FIG. 4 also illustrates that the gas transfer line 262 may be angledupwardly toward the condensing tower 271. Such an arrangement can permitany condensed material that may collect in the gas transfer line 262 toflow down the line 262 and into the knock out tank 264 (FIG. 3). Thismay be of a particular benefit when the plastic recycling system 200 isshut down and hot vapor 208 no longer flows through the gas transferline 262 so as to keep the line clear. For embodiments that do notinclude a knock out tank 264, the condensed material may instead flowdown the line 262 to any suitable fluid collection point.

With continued reference to FIG. 3, the condenser 270 can include alower sprayer 280 and an upper sprayer 282 that are separated from eachother by one or more sections of column packing 284. For example, threesections of column packing 284 may separate the upper and lower sprayers282, 280. Each of the upper and lower sprayers 282, 280 provides a sprayor shower of the pH adjusted solution 212, but at differenttemperatures. The lower sprayer 282 can provide a spray at a highertemperature (e.g., a warm temperature, such as, for example, within arange of from about 120 to about 150 degrees Fahrenheit), whereas theupper sprayer 280 can provide a spray at a lower temperature (e.g., acool temperature, such as, for example, within a range of from about 70to about 80 degrees Fahrenheit).

The lower sprayer 282 may be used primarily as a cleaning device forremoving impurities from the vapor 208. A temperature of the lowersprayer 282 may be sufficiently high to permit the pH adjusted solution212 to dissolve or absorb portions of the vapor 208 substantiallywithout condensing any other portion of the vapor 208. The sprayed pHadjusted solution 212 can drop into a reservoir 286, which is discussedfurther below. Accordingly, the lower sprayer 282 and/or the reservoir286 may be used to separate impurities from the vapor 208, and thus maybe referred to individually or collectively herein as a washing systemor cleaning system 287.

After passing through the lower sprayer 282, the remaining portion ofthe vapor 208 passes upwardly through the column packing 284 and losesenergy thereto. The vapor 208 then encounters the lower temperature pHadjusted solution 212 that is sprayed from the upper sprayer 282. Atleast a portion of the remaining vapor 208 is thus condensed and dropsinto the reservoir 286. The pH adjusted solution 212 that is sprayedfrom the upper sprayer 282 thus may also be referred to as a condensingliquid.

Those portions of the vapor 208 that are not condensed (i.e.,non-condensable gases) are then passed to a caustic scrubber 290, whichpasses the remaining vapor 208 through a caustic solution so as tochemically scrub the vapor (e.g., remove mercaptan sulfur speciestherefrom) and so as to neutralize trace levels of free inorganic acids.The remainder of the vapor 208 passes from the caustic scrubber 290through the vacuum system 224, and is then pushed to an environmentalcontrol device 292.

Any suitable vacuum system 224 may be used with the plastic recyclingsystem 200. One illustrative embodiment is depicted in FIG. 5. Thevacuum system 224 includes a first blower 294 and a second blower 296that are in parallel with each other. One or more valves 298 may beincluded in parallel with the blowers 294, 296. In such an arrangement,both blowers 294, 296 may be used at startup of the plastic recyclingsystem 200 in order to place the vapor treatment system 210 and thecontainer 222 under vacuum, whereas only one blower 294, 296 may be usedonce the recycling system 200 is operational. The vacuum system 224 maycycle between use of the blowers 294, 296 to keep their usage timesapproximately equal. Moreover, the valve 298 may be maintained in aslightly open or vented configuration, which can result in a relativelyuniform vacuum during a transition between blowers 294, 296, as well asduring sustained operation of either blower 294, 296.

In some instances, it can be desirable to maintain a vacuum in thecontainer 222, the vapor treatment system 210, and the caustic scrubber290 during operation of the system 200. For example, in someembodiments, the vacuum system 224 (which may more generally be referredto as a pressure system) provides a magnitude of negative pressure thatis sufficiently great to maintain a vacuum within the container 222, aswell as other portions of the system 200 that are in fluid communicationtherewith, even if spikes of positive pressure occur as the plasticfeedstock 206 is being vaporized. In some embodiments, the vacuum system224 maintains a negative pressure that has a magnitude of no less thanabout 8, 10, or 12 inches of water column.

In other embodiments, a pressure system may provide a positive pressurewithin the container 222, the vapor treatment system 210, and thecaustic scrubber 290. In still other embodiments, a pressure system(e.g., the vacuum system 224) may be omitted from or not used in theplastic recycling system 200. For example, atmospheric pressureconditions may be maintained within the container 222, the vaportreatment system 210, and the caustic scrubber 290. Providing higherpressures to the plastic recycling system 200 can cause the vapor 208 tobe heated for longer periods within the container 222, which can resultin greater depyrolization and lighter organic molecules within the vapor208. Under such conditions, more fuel from the fuel train 234 may beconsumed to provide the vapor 208 with sufficient energy to pass throughthe system 210.

Any suitable environmental control device 292 can be used with theplastic recycling system 200. In some embodiments, the environmentalcontrol device 292 can comprise a burner or other combustion device. Forexample, in some embodiments, the environmental control device 292 cancomprise a CEB® clean enclosed burner, which is available from N. V.Bekaert S. A., of Kortrijk, Belgium. In the illustrated embodiment,exhaust from the environmental control device 292 is shown as beingvented to atmosphere. In other embodiments, the hot exhaust may insteadbe transferred to other portions of the plastic recycling system 200.For example, in some embodiments, exhaust from the environmental controldevice 292 can be delivered to the heating system 202 and may be used toheat the container 222.

Referring again to the reservoir 286, the absorbed and condensedportions of the vapor 208 drop into a tank 300 that includes a weir 302at an upper edge thereof. The pH adjusted solution 212, which retainsthe absorbed impurities, may facilitate coagulation of some contaminantswhich have a greater relative density than the condensed crude oilmaterial, and may settle to the bottom of the tank 300. Accordingly, thecondensed crude oil rises to the top of the tank 300 and flows over theweir 302 into a temporary containment region 304. At this stage, thecrude oil may be slightly emulsified with the pH adjusted solution 212(e.g., may have a small quantity of pH adjusted solution 212 entrainedtherein), and thus this material that consists primarily of crude oilmay be referred to as an emulsion 226. As discussed further below, theemulsion 226 can be removed from the containment region 304 anddelivered to a separator or settling tank 228.

The pH adjusted solution 212 within the tank 300 can be cycled to thelower and upper sprayers 280, 282. In particular, a circulation pump 310can move solution 212 from the tank 300 through a fluid line 312 to eachof the sprayers 280, 282. The pressure and temperature at the lower andupper sprayers 280, 282 can be monitored by separate pressure sensors314, 318 and separate temperature sensors 316, 320, respectively. Aportion of the fluid line 312 can pass through a heat exchanger 322,which is coupled to a cooling system 324 through a cooling loop 326. Thecooling system 324 can be of any suitable variety, and may include acooling tower and/or a chiller. A cooling line pump 328 can control aflow of cooling fluid through the cooling loop 326. Pressure andtemperature at each of the sprayers 280, 282 can be controlled byadjusting one or more settings of the circulation pump 310, the coolingline pump 328, the cooling system 324, and/or a valve 330 associatedwith the lower sprayer 280 and a valve 332 associated with the uppersprayer 332.

As previously discussed, in some embodiments, it is desirable tomaintain the lower sprayer 280 at a temperature that is within a rangeof from about 120 to about 150 degrees Fahrenheit. Such a temperaturerange can be too high to effect condensation of organic molecularspecies that are within the vapor 208, and may also facilitateabsorption of impurities from the vapor 208. Additionally, crude oilthat collects in the tank 300 and in the containment region 304 can bein a liquid or free flowing state within it is within such a temperaturerange, or when it is at a temperature slightly above such a range.Accordingly, when the solution 212 that is ejected from the lowersprayer 280 is within such a temperature range, the solution 212 and theemulsion 226 that are in the reservoir 286 can be maintained at atemperature that is within this temperature range, or that is higherthan this range, due to absorption of heat from the incoming vapor 208.

In some embodiments, it is desirable to maintain the upper sprayer 282at a temperature that is within a range of from about 70 to about 80degrees Fahrenheit. For example, such a temperature range can be wellsuited for condensing organic molecules. Additionally, it can bedesirable for certain gases exiting the vapor treatment system 210(e.g., methane, ethane, propane, and/or butane) to remain in a gaseousstate so that they may be burned more readily in the environmentalcontrol device 292. Accordingly, data obtained by a temperature sensor340 that is at an exit port of the vapor treatment system 210 can beused in adjusting a temperature of the upper sprayer 282 to a desiredvalue.

In other embodiments, the vapor treatment system 210 may include asingle sprayer, such as the upper sprayer 282. The single sprayer 282can simultaneously effect both absorption of impurities and condensationof the crude oil. In certain of such embodiments, it may be desirable toadd to or alter certain separation steps discussed below, since theresultant emulsion 226 may include a greater number of impurities (e.g.,due to a greater degree of entrainment of the pH adjusted solution 212and/or dissolved or free impurities within the crude oil 218). Forexample, it may be desirable to permit the emulsion 226 to settle withinthe settling tank 228 for a longer period of time.

As the pH adjusted solution 212 absorbs impurities from the vapor 208, acomposition of the solution can change. For example, in someembodiments, the pH adjusted solution 212 may become more or lessacidic. Accordingly, in some embodiments, a pH sensor 342 can beincluded within the tank 300 to monitor the composition of the solution212. The fluid line 312 can include an pH adjustment port 344 throughwhich an acid or other suitable material may be added to the solution212 that is circulated from the reservoir 286. For example, an acid maybe introduced into the fluid line via the pH adjustment port 344 when itis determined from the pH sensor 342 that the acidity of the solution212 has dropped. Water from a makeup water source 345 may be added tothe fluid line 312. For example, if an acidic level of the pH adjustedsolution 212 that is within the reservoir 286 has increased beyond anupper threshold, water from the makeup water source 345 may be added tothe fluid line 312.

In some embodiments, a temperature sensor 350 is included in thereservoir 286 (e.g., within the tank 300) to ensure that the temperatureof the reservoir 286 does not drop below a desired level. For example,as previously discussed, it may be desirable to maintain the temperaturewithin the reservoir 286 at a level at which the oil or emulsion 226 isin a liquid or flowable state. A heating element 352 may be used inconjunction with the temperature sensor 350 to keep the oil and waterwithin the reservoir 286 warm, such as during periods of shutdown.

In certain embodiments, the reservoir 286 includes a level sensor 354 tomonitor a level of the oil or emulsion 226 and includes another levelsensor 356 to monitor a level of the pH adjusted solution 212. Dataobtained from the level sensor 354 can be used in controlling a pump360, which is configured to pump emulsion 226 from the temporarycontainment region 354 to the settling tank 228. The pump 360 maycomprise any suitable variety of pump, and may be well suited forpumping thick material which may be highly viscous. For example, thepump 360 may comprise a positive displacement pump.

The emulsion 226 can be pumped through a heat traced line 361 into aseparation tank 362 contained within the settling tank 228. Theseparation tank 362 can include angled sidewalls 363 and an entry baffle364. The separation tank 362 can encourage further separation of thecrude oil 218 from the pH adjusted solution 212, such as by separationdue to relative densities. The crude oil 218 can flow over an upper edgeof the separation tank 362 into a holding area 366. The crude oil 218can removed from the holding area 366 and stored or transported asdesired. For example, the oil 218 can be moved to a storage tank ortransported to a refinery (e.g., via an oil tanker).

The crude oil 218 may be relatively waxy and solid at room temperature.Accordingly, it may be desirable to maintain the crude oil 218 in aliquid form to facilitate separation of the solution 212 therefromand/or removal of the oil 218 from the settling tank 228. The settlingtank thus may include a temperature sensor 369, which can be used toselectively activate a heating fluid loop 370 that is in communicationwith the heat exchanger 248. A heating line pump 372 can control theflow of heating fluid through the heating fluid loop 370.

Removal of the crude oil 218 from the settling tank 228 is illustratedby the arrow 374. The pH adjusted solution 212 likewise can be removedfrom the settling tank 228, as indicated by the arrow 376. In someembodiments, the pH adjusted solution 212 is returned to the reservoir286, and may thereafter be cycled through the sprayers 280, 282.

With continued reference to FIG. 3, it is again noted that duringoperation of the heating system 202 and the container 222, heated air iscirculated within the heating plenum 232 so as to melt the plasticfeedstock 206 and convert it into one or more gases within the vapor208. A vacuum is applied via the evacuation port 261 so as to remove thevapor 208 from the container 222. The removed gases can then beprocessed as desired.

Upon removal of all or substantially all of the desired gases from thecontainer 222, the container 222 can be removed from the heating plenum232 and replaced with an additional container 222 that has been chargedwith a quantity of the plastic feedstock 206. The foregoing heating avapor removal processes can then be repeated, and the removed container222 can be cleaned and charged with plastic feedstock 206 for futureuse. The successive coupling, heating, removal, and replacement of aseries of charged containers 222 for a single heating plenum 232 can bereferred to as a batch process.

FIG. 6 illustrates another embodiment of the plastic recycling system200 in which plastic feedstock may be vaporized and processed in amanner that is referred to herein as a continuous batch process. Theplastic recycling system 200 can be identical to the embodimentsdescribed above with respect to FIG. 3, except that the system 200includes four separate heating systems 202A, 202B, 202C, 202D, each witha separate burner 230A, 230B, 230C, 230D that is configured to heat aseparate heating plenum 232A, 232B, 232C, 232D. Although not shown inFIG. 6, an optional exhaust path from each of the heating plenums 232A,232B, 232C, 232D can be provided to the heat exchanger 248 (see FIG. 3).

Each heating plenum 232A, 232B, 232C, 232D is configured to receive aseparate container 222A, 222B, 222C, 222D therein, and each containercan be filled with a separate quantity of plastic feedstock 206A, 206B,206C, 206D. As illustrated in FIG. 6, a first container 222A can beinserted in a first heating plenum 232A and heated for a first period oftime; a second container 222B can be inserted in a second heating plenum232B at the end of the first period, and both the first and secondcontainers 222A, 222B can be heated for a second period; a thirdcontainer 222C can be inserted in a third heating plenum 232C at the endof the second period, and the first, second, and third containers 222A,222B, 222C can be heated for a third period; and a fourth container 222Dcan be inserted in a fourth heating plenum 232D at the end of the thirdperiod, and the first, second, third, and fourth containers 222A, 222B,222C, 222D can be heated for a fourth period.

FIG. 6 illustrates a point in time at the end of the fourth period ofheating time. As shown, nearly all of the plastic feedstock 206A hasbeen vaporized and removed from the container 222A, such that only solidcarbon material (e.g., non-hydrocarbon product) remains. By comparison,all of the plastic feedstock 206B has been melted within the secondcontainer 222B, and a portion thereof has been vaporized and removed;all of the plastic feedstock 206C has been melted within the thirdcontainer 222C, but relatively little has been vaporized and removed;and only some of the plastic feedstock 206D has been melted within thefourth container 222D.

At this point in time, a filled fifth container 222E can be positionednear the first heating plenum 232A. The first container 222A can then beremoved from the first heating plenum 232A and the fifth container 222Ecan be introduced into the first heating plenum 232A in its place. Thefifth, second, third, and fourth containers 222E, 222B, 222C, 222D canthen be heated for a fifth period of time. Replacement of a singlecontainer 222 at the end of a heating period can continue in series foreach of the second, third, and fourth containers 222B, 222C, 222D,respectively, and can cycle through to the fifth heating plenum 222E.

As shown in FIG. 6, each of the containers 222A, 222B, 222C, 222D can beconnected to the gas transfer line 262, which can supply a negativepressure via the vacuum system 224 (FIG. 3), as described above. Vapors,such as the vapors 208C, 208D, thus can be mixed within the gas transferline 262 as they are delivered to the vapor treatment system 210. Suchan arrangement thus can be relatively insensitive to the species ofmolecules that are contained within a vapor 208 from any given container222. This insensitivity to molecular species can be particularly usefulfor a continuous batch mode operation, since the vaporization processcan proceed without careful coordination among the various heatingsystems 202A, 202B, 202C, 202D to ensure that only a single molecularspecies is drawn simultaneously from the containers 222A, 222B, 222C,222D. Stated otherwise, the recycling system 200 can operate properly,even when a variety of different molecular species are introduced intothe vapor 206 of any given container 222 and/or even when a variety ofdifferent molecular species are introduced into the common gas transferline 262 from multiple containers 222.

The gas transfer line 262 can include a series of pressure sensors 266A,266B, 266C, 266D and/or temperature sensors 268A, 268B, 268C, 268D,which can be used in determining whether a container 222 is ready to bereplaced, as discussed above. In other or further embodiments, the gastransfer line 262 can include a series of valves 384, which may bemanipulated so as to permit removal of a container 222 withoutinterrupting vapor collection from the remaining containers 222. In someembodiments, the recycling system 200 includes an inert gas purge system380 that can be used to flush any portion of the gas transfer line 262.The inert gas purge system 380 can include a series of valves 382, whichmay be manipulated appropriately to introduce an inert gas wheredesired. In some instances, nitrogen or some other inert gas may be usedto purge a full section of the gas transfer line 262 from process gasesbefore removal of a spent container 222 and/or may be used to purgeoxygen from (or to dilute oxygen within) a portion of the gas transferline 262 after a new cartridge 222 has been connected thereto.

Measures may be taken to prevent or reduce heat losses when a container222 is removed from its respective plenum 232 and replaced. For example,in some embodiments, a burner 230 is turned off just prior to removal ofa container 222 from the associated heating plenum 232, and air can bedrawn down into the heating plenum 232 as the container 222 is removedand replaced. The burner 230 can then be activated again once the newcontainer 222 is in place.

The illustrated embodiment of the recycling system 200 includes fourheating plenums 232. In some instances, a total of eight containers 222may be used effectively with such a system, as some spent containers maybe cleaned and filled while the remaining containers are in use.However, more or fewer containers may be used with such a system.Likewise, more or fewer heating plenums may be used in continuous batchprocesses.

FIG. 7 illustrates another embodiment of a plastic recycling system 200,which is similar to the system 200 illustrated in FIG. 3. Like thesystem 200, the system 200 includes a vacuum system 224 and a causticscrubber 290. However, the vacuum system 224 is situated in line withthe scrubber 290 between the vapor treatment system 210 and the scrubber290, rather than between the scrubber 290 and the environmental controldevice 292. The output of the scrubber 290 thus may be delivereddirectly to the environmental control device 292.

Other embodiments of the systems 200, 200 may each have multiple vaportreatment systems 210, which may each receive vapor 208 from one or morecontainers 222 within one or more heating systems 202. In arrangementssimilar to that shown in FIG. 7, the outputs of the multiple vaportreatment systems 210 may be delivered to an input end of the vacuumsystem 224, and a single output of the vacuum 224 may be delivered tothe scrubber 290. In arrangements similar to that shown in FIG. 3, theoutputs of the multiple vapor treatment systems 210 may each bedelivered to an input end of a separate scrubber 290, such that theplastic recycling system 200 comprises multiple scrubbers 290. Theoutputs of the multiple scrubbers 290 can be delivered to a singlevacuum system 224, and the vacuum system 224 can have a single outputthat is in fluid communication with the environmental control device292. In still further embodiments, a single plastic recycling system 200or 200 can include multiple vacuum systems 224 and multiple scrubbers290.

FIG. 8 illustrates another embodiment of a plastic recycling system 400,which can resemble the plastic recycling systems 200, 200 in manyrespects. Accordingly, like features are identified with like referencenumerals. Moreover, specific features of the recycling system 400 maynot be identified by reference numerals in the drawings or specificallydiscussed in the written description that follows. However, suchfeatures may clearly be the same, or substantially the same, as featuresdepicted in other embodiments and/or described with respect to suchembodiments. Accordingly, the relevant descriptions of such featuresapply equally to the features of the recycling system 400. Any suitablecombination of the features and variations of the same described withrespect to the recycling system 200 can be employed with the recyclingsystem 400, and vice versa. This pattern of disclosure applies equallyto further embodiments depicted in subsequent figures and describedhereafter.

The recycling system 400 includes a heating system 402 that isconfigured to depolymerize a plastic feedstock 206 in a continuousmanner. In the illustrated embodiment, the heating system 402 comprisesa heating unit 431 of any suitable variety, such as a fluidized bedburner 432 that is configured to effect rapid depolymerization of theplastic feedstock 206. Other suitable heating devices are also possible.The plastic feedstock 206 can be fed into the heating unit 431 by agravity feed hopper 433 or any other suitable feeding mechanism that canprovide a continuous supply of the plastic feedstock 206 to thefluidized bed burner 432. If desired, the plastic feedstock may beprovided under vacuum or inert gas conditions.

FIG. 9 illustrates a portion of another embodiment of a plasticrecycling system 500, which can be used in such plastic recyclingsystems as those described with respect to FIGS. 3, 7, and 8 (e.g., therecycling systems 200, 200, 400). Accordingly, like features areidentified with like reference numerals. The system 500 includes a vaportreatment system 510 that includes a washing system or cleaning system587 and a condenser 570. The cleaning system 587 includes a cleaningtank 585 that has a quantity of the pH adjusted solution 212 therein.The condenser 570 includes a reservoir 586 that resembles the reservoir286 described above and contains a condensing liquid 213.

A vapor 208 can be introduced into the cleaning system 587 from a gastransfer line 262. The vapor 208 is placed into direct contact with thepH adjusted solution 212 within the cleaning tank 585. For example thevapor 208 can be bubbled through the pH adjusted solution 212. In thisprocess, impurities may absorbed from the vapor 208 so as to beextracted therefrom. The solution 212 may be held at a temperature thatis sufficiently high to prevent organic molecules from condensingtherein.

After having been bubbled through the solution 212, the remaining vapor208 can be removed from the cleaning tank 585 and delivered into thereservoir 586. The condensing liquid 213 can be maintained at arelatively low temperature and can be capable of condensing organicmolecules from the vapor 208. The vapor 208 thus can be bubbled throughthe condensing liquid 213, and condensed organic molecules can collectabove the condensing liquid 213 as a crude oil emulsion 226.Non-condensable gases can be drawn from the reservoir 286 through acaustic scrubber 290 via a vacuum system 224. Emulsion 226 that hasspilled over a weir 302 can be drawn from the reservoir via a pump 260for delivery to a settling tank 228 (see FIG. 3) for further separation.

The condensing liquid 213 can be maintained at a temperature that islower than that of the pH adjusted solution 212. In some embodiments, acomposition of the condensing liquid 213 and the pH adjusted solution212 are the same (e.g., the condensing liquid 213 comprises a quantityof the pH adjusted solution 212). However, in other embodiments, thecondensing liquid 213 may have a different composition. For example, thecondensing liquid 213 may comprise neutral water.

It will be understood by those having skill in the art that changes maybe made to the details of the above-described embodiments withoutdeparting from the underlying principles presented herein. For example,any suitable combination of various embodiments, or the featuresthereof, is contemplated. For example, various embodiments may beconfigured to operate in one or more of a batch mode, a continuous batchmode, or a continuous mode. Other or further embodiments may include acondenser system and/or other components (e.g., a container) that areconfigured to operate under one or more of vacuum conditions,atmospheric pressure conditions, or positive pressure conditions.

Any methods disclosed herein comprise one or more steps or actions forperforming the described method. The method steps and/or actions may beinterchanged with one another. In other words, unless a specific orderof steps or actions is required for proper operation of the embodiment,the order and/or use of specific steps and/or actions may be modified.

Throughout this specification, any reference to “one embodiment,” “anembodiment,” or “the embodiment” means that a particular feature,structure, or characteristic described in connection with thatembodiment is included in at least one embodiment. Thus, the quotedphrases, or variations thereof, as recited throughout this specificationare not necessarily all referring to the same embodiment.

Similarly, it should be appreciated that in the above description ofembodiments, various features are sometimes grouped together in a singleembodiment, figure, or description thereof for the purpose ofstreamlining the disclosure. This method of disclosure, however, is notto be interpreted as reflecting an intention that any claim require morefeatures than those expressly recited in that claim. Rather, inventiveaspects lie in a combination of fewer than all features of any singleforegoing disclosed embodiment. It will be apparent to those havingskill in the art that changes may be made to the details of theabove-described embodiments without departing from the underlyingprinciples set forth herein.

The claims following this Detailed Description are hereby expresslyincorporated into this Detailed Description, with each claim standing onits own as a separate embodiment. This disclosure includes allpermutations of the independent claims with their dependent claims.Recitation in the claims of the term “first” with respect to a featureor element does not necessarily imply the existence of a second oradditional such feature or element. Elements specifically recited inmeans-plus-function format, if any, are intended to be construed inaccordance with 35 U.S.C. §112 ¶ 6. Embodiments of the invention inwhich an exclusive property or privilege is claimed are defined asfollows.

1. A method of recycling plastic, the method comprising: heating acontainer that has a plastic feedstock therein so as to effectdepolymerization of the plastic feedstock; removing a vapor from theheated container, wherein the vapor comprises a gaseous organic speciesand a gaseous inorganic species; condensing the gaseous organic speciesand separating the condensed organic species from the inorganic speciesby directly contacting the vapor with a pH adjusted solution, whereinthe condensed organic species is less dense than water and ishydrophobic, wherein separating the condensed organic species from theinorganic species comprises retaining the condensed organic species andthe pH adjusted solution into which the inorganic species has beenabsorbed in a common tank, and wherein directly contacting the vaporwith the pH adjusted solution causes absorption of the inorganic speciesinto the solution; introducing at least a portion of the condensedorganic species that has been separated from the inorganic species intoa settling tank to permit further additional pH adjusted solution to beseparated from the condensed organic species; and returning pH adjustedsolution that has separated from the condensed organic species back tothe tank.
 2. The method of claim 1, wherein the organic speciescomprises a class of polar organic molecules.
 3. The method of claim 1,further comprising: removing additional vapor from additional containersin a continuous batch mode, wherein the additional vapor comprises agaseous organic species and a gaseous inorganic species; and condensingthe gaseous organic species of the additional vapor and separating thecondensed organic species of the additional vapor from the inorganicspecies of the additional vapor by directly contacting the additionalvapor with the pH adjusted solution.
 4. The method of claim 1, whereinheating the container comprises providing heated air to an exterior ofthe container at a steady temperature during a transition of a pluralityof molecular species from the plastic feedstock into the vapor, whereineach of the plurality of molecular species has a different vaporizationtemperature at a given pressure.
 5. A method of recycling plastic, themethod comprising: heating a plastic feedstock under negative pressureso as to effect depolymerization of the plastic feedstock and so as toproduce a vapor that comprises a first component and a second component,wherein the first component comprises a gaseous organic species and thesecond component comprises one or more of an atomic species and amolecular species; condensing the gaseous organic species and separatingthe condensed organic species from the second component by directlycontacting the vapor with a pH adjusted solution.
 6. The method of claim5, wherein at least a portion of the second component of the vapor is ina gaseous state before the vapor is directly contacted with the pHadjusted solution.
 7. The method of claim 6, wherein directly contactingthe vapor with a pH adjusted solution condenses at least a portion ofthe second component.
 8. The method of claim 5, wherein the secondcomponent of the vapor comprises one or more of a metal species, a polarorganic species, an organic acid species, and inorganic acid species. 9.The method of claim 5, wherein the organic species of the firstcomponent of the vapor comprises one or more species of non-polarorganic molecules.
 10. The method of claim 5, wherein directlycontacting the vapor with the pH adjusted solution causes absorption ofat least a portion of the second component into the solution, whereinthe condensed organic species of the first component is less dense thanwater and is hydrophobic, and wherein separating the condensed organicspecies from the second component comprises retaining the condensedorganic species and the pH adjusted solution into which at least aportion of the second component has been absorbed in a common reservoir.11. The method of claim 10, wherein separating the condensed organicspecies from the second component further comprises permitting at leasta portion of the condensed organic species to flow over an upper edge ofthe reservoir while retaining the pH adjusted solution into which atleast a portion of the second component has been absorbed within aseparate region of the reservoir.
 12. The method of claim 5, whereinsaid directly contacting the vapor with a pH adjusted solution comprisesbubbling the vapor through the pH adjusted solution.
 13. The method ofclaim 5, wherein said directly contacting the vapor with a pH adjustedsolution comprises spraying the vapor with the pH adjusted solution. 14.The method of claim 13, wherein directly contacting the vapor with thepH adjusted solution causes absorption of at least a portion of thesecond component into the solution, wherein the condensed organicspecies is less dense than water and is hydrophobic, and whereinseparating the condensed organic species from the second componentcomprises retaining the condensed organic species and the pH adjustedsolution into which at least a portion of the second component has beenabsorbed in a common reservoir, the method further comprising sprayingadditional vapor obtained from the plastic feedstock with the pHadjusted solution into which the second species has been absorbed.
 15. Amethod of recycling plastic, the method comprising: heating a plasticfeedstock under negative pressure so as to effect depolymerization ofthe plastic feedstock and so as to produce a vapor that comprises afirst component and a second component, wherein the first componentcomprises a gaseous organic species and the second component comprisesone or more of an atomic species and a molecular species; and condensingthe first component of the vapor and separating at least a portion ofthe second component from the first component by directly contacting thevapor with a pH adjusted solution at a first temperature, whereincondensing the first component results in a condensed organic speciesand separation of the first component from the second component, andwherein the separation of the first component from the second componentoccurs as the second component is absorbed into the pH adjustedsolution.
 16. The method of claim 15, further comprising separating thecondensed organic species from the second component absorbed into the pHadjusted solution after having condensed the first component of thevapor.
 17. The method of claim 15, wherein the condensed organic speciesand a portion of the pH adjusted solution into which at least a portionof the second component of the vapor has been absorbed are includedtogether in an emulsion; the method further comprising separating thecondensed organic species from the pH adjusted solution.
 18. The methodof claim 15, wherein directly contacting the vapor with a pH adjustedsolution comprises spraying the vapor.
 19. A method of recyclingplastic, the method comprising: heating a plastic feedstock undernegative pressure so as to effect depolymerization of the plasticfeedstock and so as to produce a vapor that comprises a first componentand a second component, wherein the first component comprises a gaseousorganic species and the second component comprises one or more of anatomic species and a molecular species; absorbing at least a portion ofthe second component of the vapor by directly contacting the vapor witha pH adjusted solution at a first temperature; and condensing the firstcomponent of the vapor to form a condensed organic species by directlycontacting the vapor with a condensing liquid at a second temperature.20. The method of claim 19, wherein a composition of the pH adjustedsolution and a composition of the condensing liquid are the same. 21.The method of claim 19, wherein the condensed first component of thevapor and the condensing liquid are included together in an emulsion;the method further comprising separating the condensed organic speciesfrom the condensing liquid.
 22. A method of recycling plastic, themethod comprising: introducing a first cartridge that contains a firstquantity of plastic feedstock into a first heating plenum; introducing asecond cartridge that contains a second quantity of plastic feedstockinto a second heating plenum; heating both the first and secondcartridges such that the first quantity of plastic feedstock yields afirst vapor and the second quantity of plastic feedstock yields a secondvapor; introducing the first and second vapors into a vapor treatmentsystem; and condensing the first and second vapors by simultaneouslycontacting the first and second vapors with a pH adjusted solution. 23.The method of claim 22, further comprising combining at least a portionof the first and second vapors within a gas transfer line prior tointroducing the first and second vapors into the vapor treatment system.24. The method of claim 22, wherein heating both the first and secondcartridges comprises providing heated fluid to the first heating plenumfrom a first burner and providing heated fluid to the second heatingplenum from a second burner that is independent of the first burner. 25.The method of claim 24, further comprising: removing the first cartridgefrom the first heating plenum; introducing a third cartridge thatcontains a third quantity of plastic feedstock into the first heatingplenum; and heating the third cartridge such that the third quantity ofplastic feedstock yields a third vapor.
 26. The method of claim 25,further comprising combining at least a portion of the third vapor andat least a portion of the second vapor within a gas transfer line; andintroducing the combined portions of the third and second vapors intothe vapor treatment system.
 27. The method of claim 25, furthercomprising maintaining operation of the second burner so as to heat thesecond container while removing the first cartridge from the firstheating plenum and while introducing the third cartridge into the firstheating plenum.
 28. The method of claim 22, wherein condensing the firstand second vapors by simultaneously contacting the first and secondvapors with a pH adjusted solution takes place after the first andsecond vapors have been introduced into the vapor treatment system. 29.A plastic recycling system comprising: a sealable container having aplastic feedstock therein, the container comprising a port; a heatingsystem configured to receive the container and to apply heat thereto inan amount sufficient to result in depolymerization of the plasticfeedstock; a gas transfer system coupled with the port of the containerso as to remove vapor from the container through the port and into thegas transfer system; and a vapor treatment system in fluid communicationwith the gas transfer system, the vapor treatment system comprising acondenser utilizing a pH adjusted solution, wherein the condenser isconfigured to condense an organic molecular species from the vapor byeffecting direct contact between the pH adjusted solution and vapor thatis received into the vapor treatment system from the gas transfersystem.
 30. The system of claim 29, wherein the vapor treatment systemfurther comprises a reservoir that contains at least a portion of the pHadjusted solution, wherein the reservoir is configured to receive thecondensed organic molecular species.
 31. The system of claim 30, whereinthe reservoir comprises a weir such that at least a portion of thecondensed organic molecular species can flow over an edge of the weir soas to be separated from the pH adjusted solution.
 32. The system ofclaim 29, wherein the vapor treatment system comprises a first sprayerthat is configured to spray the vapor with the pH adjusted solution at afirst temperature.
 33. The system of claim 32, wherein the vaportreatment system further comprises a second sprayer that is configuredto spray the vapor with the pH adjusted solution at a secondtemperature, wherein the first temperature is higher than the secondtemperature.
 34. The system of claim 33, wherein the first sprayer ispositioned lower than the second sprayer such that a portion of thevapor rises toward the second sprayer after having been sprayed by thefirst sprayer.
 35. The system of claim 29, further comprising a coolingsystem configured to maintain the pH adjusted solution that is used fordirect contact with the vapor at a temperature lower than that of thevapor.
 36. The system of claim 29, further comprising a vacuum systemthat is in fluid communication with the container when the container issealed and is configured to maintain negative pressure within thecontainer during heating thereof.
 37. The system of claim 36, whereinthe vacuum system is in fluid communication with the vapor treatmentsystem and the gas transfer system and is configured to maintainnegative pressure within the vapor treatment system and the gas transfersystem during operation of the plastic recycling system.
 38. The systemof claim 29, further comprising: a control system; and one or more of atemperature sensor and a pressure sensor in communication with thecontrol system and positioned to obtain measurements of the vapor,wherein the control system is configured to adjust or terminate anamount of heat delivered to the container by the heating system inresponse to the measurements.
 39. The system of claim 29, furthercomprising a settling tank and a pump that is in fluid communicationwith the vapor treatment system, wherein the pump is configured totransport at least a portion of the condensed organic molecular speciesto the settling tank.
 40. The system of claim 29, further comprising anenvironmental control device, wherein non-condensable components of thevapor are delivered from the condenser system to the environmentalcontrol device.
 41. The system of claim 40, wherein the environmentalcontrol device provides heated exhaust to a portion of the heatingsystem.